README.md

$ ansible-playbook -i hosts -c local playbook.yml 

PLAY [main[0]] *******************************************************************************************************************************************************************************************************************************

TASK [Gathering Facts] ***********************************************************************************************************************************************************************************************************************
ok: [127.0.0.1]

TASK [command] *******************************************************************************************************************************************************************************************************************************
changed: [127.0.0.1]

TASK [debug] *********************************************************************************************************************************************************************************************************************************
ok: [127.0.0.1] => {
    "msg": "0.0.0.0"
}

PLAY RECAP ***********************************************************************************************************************************************************************************************************************************
127.0.0.1                  : ok=3    changed=1    unreachable=0    failed=0   

hosts

[main]
127.0.0.1 private_ip=0.0.0.0
192.168.0.53 private_ip=0.0.0.0

playbook.yml

- hosts: main[0]
  tasks:   
    - command: echo "Hey Asshole"
      register: out
    - debug: 
        msg: "{{  hostvars[groups['main'][1]].private_ip}}"